Modified 128-QAM Constellation Schemes Allowing Low-complexity Non-Data-Aided Carrier Recovery

Conference: PIMRC 2005 - 16th Annual IEEE International Symposium on Personal Indoor and Mobile Radio Communications
09/11/2005 - 09/14/2005 at Berlin, Germany

Proceedings: PIMRC 2005

Pages: 5Language: englishTyp: PDF

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Hou, Hsin-An (Computer & Communications Research Laboratories, Industrial Technology Research Institute, Chutung, Hsinchu, Taiwan, ROC)

Squared M-ary quadrature amplitude modulation (QAM) constellations have been widely adopted for modern high-data-rate digital communications. Nevertheless, carrier recovery required by demodulation of 128-QAM signals is almost a formidable task for practical receiver design. In this paper, two types of modified 128-QAM constellations are proposed allowing utilization of a low-complexity carrier recovery mechanism in the receiver. With the proposed constellations, perfect recovery of a frequency offset up to ±2.5% of baud rate is guaranteed using a conventional carrier recovery method at the expense of slight Es/N0 and PAPR increment compared with the conventional 128-QAM constellations.